Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1111 am EDT Sat Jul 26 2014
high pressure over the region moves into the western Atlantic on
today. An upper level trough of low pressure moves into the area
on Sunday and brings showers and isolated thunderstorms through
Monday or Tuesday. High pressure builds in again for later in the
Near term /today/...
made only minor modifications to adjust hourly temperature trends.
Sky and pop forecast still on track with cumulus building in the
mountains leading to a slight chance of showers this afternoon.
mostly minor changes to account for current observational trends.
Otherwise...large area of dense smoke will continue to lift NE as
SW flow takes over aloft. Haze forecast in the grids looks on track
for when improving visibility can be expected.
smoke from Forest fires 2500 miles away continues to leave much of
the area in a haze this morning. In fact if you get outside before
sunrise begins to mix the boundary layer...you may be able to
smell the smoke in the air. Until that time will keep haze in the
grids. At the moment patchy valley fog is also developing. These
visibility restrictions will persist through about 12z.
Increasing SW flow today will aid in clearing out the smoke...as
well as bumping temperatures up a few degrees from Friday. Expect
another afternoon of diurnal cumulus development...and perhaps a few
showers in the high terrain. Lapse rates are fairly poor...so have
not added thunder to the forecast.
Short term /tonight and Sunday/...
an approaching cold front will begin to spread clouds across the
area tonight. That and continued SW flow will keep temperatures
more on the mild side...especially compared to the past couple
By Sunday front will try and cross the area. As it does so expect
widespread shower activity. Lapse rates do improve for the
afternoon...so thunder remains in the forecast. The best
thermodynamic profile will be much farther SW...across the middle
Atlantic...however cannot rule out an isolated stronger
storm...especially in southern zones as shear will be supportive of
Long term /Sunday night through Friday/...
a longwave trough producing a broad cyclonic flow gets carved out
and sharpens to our west Sunday night and through next week. An
initial strong shortwave rotates through this trough into New
England Sunday night and into Tuesday before moving east...thus
numerous showers/thunderstorms are expected in that time frame. By
midweek some clearing takes place but some clouds and a few
diurnal afternoon showers may develop as the the mean longwave
trough remains to our west.
Used a blend of models...HPC guidance for quantitative precipitation forecast...for the outlook
Aviation /15z Saturday through Wednesday/...
short term...smoke from Forest fires in Canada continues to leave
the area in a haze. This should gradually disperse
today...especially as winds pick up from the SW. Until then haze and
patchy valley fog will be possible. Otherwise expect VFR
conditions through the day Saturday. Tonight and especially into
Sunday...an approaching cold front will bring a chance for rain and
MVFR or lower conditions.
Long term...unsettled weather with showers/thunderstorms and
MVFR/IFR conditions through Tuesday with slowly improving conditions
Tuesday and VFR conditions by Wednesday.
short term...southwest flow strengthens over the waters as the
center of high pressure moves offshore and a trough of low
pressure approaches from the west. Currently expect winds to stay
below Small Craft Advisory levels. Guidance continues to forecast 5 to 6 feet
seas by Sunday...however this is typically an overestimate in SW
flow. A marginal Small Craft Advisory may be needed Sunday regardless.
Long term...S flow ahead of an approaching cold front will likely
warrant a Small Craft Advisory over the outer waters Sunday night through Monday
night mainly due to building seas but possibly for some wind gusts
as well. The front stalls near or just east of the waters Tuesday
through Wednesday keeping winds and seas below Small Craft Advisory levels.
Near term update... Kimble